Modeling And Control of a Continuous Ethanol Fermentation Using a Mixture of Enzymatic Hydrolysate and Molasses from Sugarcane

Abstract

In this work, a kinetic model considering the effect of temperature was employed to assess the dynamic behavior of an ethanol fermentation process. To calibrate the model, experimental data were obtained from batch cultures using cellulosic hydrolysate from sugarcane bagasse blended with sugarcane molasses at 75% and 25% in volume, respectively, as carbon sources. The kinetic model with its parameters is applied in the simulation of a continuous fermentation process for ethanol production. The system is a typical large-scale industrial process consisting of four fermenters attached in series and operated with cell recycling. Based on dynamic simulation of the process, a suitable Infinite-Horizon Model Predictive Control (IH-MPC) was applied to deal with the fluctuation of the sugar concentration in the raw material. The control objective is to maintain the outlet sugar concentration of the fourth reactor at a desired value, by manipulating the feed flow rate. This strategy was tested for both disturbance rejection (regulatory problem) and changes in the output reference (servo problem).